Mr

Since 222Rn is not a gamma emitter, the activity of 226Ra in BqL-1 was used to determine 222Rn's activity. Equation 1 was used to calculate the activity of 222Rn.
A_(〖222〗_Rn ) = A_(〖226〗_Ra ) [1-e^(-(λ_(〖222〗_Rn ) ) T_d ) ] (Equation 1)
The decay time duration between sample collection and sample counting (T_d) was in the range of 5.0×106 ≤ T_d ≤ 9.0×106 with a factor of 106 seconds. In Equation 1 the term e^(-(λ_(〖222〗_Rn ) ) T_d ) simplified to zero and the activity of 222Rn was found to be equal to the activity of 226Ra i.e.